Differences between osteoradionecrosis and medication-related osteonecrosis of the jaw

The appearance of osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ) is similar, but clinically important differences between ORN and MRONJ exist. The aim of this study was to compare the clinical data between ORN and MRONJ and to reveal the critical differences between these diseases.

We retrospectively reviewed the epidemiological data, clinical findings, and treatment in 27 ORN and 61 MRONJ patients. Radiographic signs before the initiation of treatment were also assessed.

The median age (P = 0.0474) and the ratio of female to male patients (P < 0.0001) were significantly higher in MRONJ patients. There were significantly more MRONJ patients who reported a history of pain when compared with ORN patients (P = 0.0263). As an aetiological factor, tooth extraction was significantly more relevant to MRONJ than ORN (P = 0.0352). When assessing the radiographic signs on computed tomographic images, periosteal reaction was found only in MRONJ patients (P = 0.0158). Minimal debridement was performed significantly more frequently for MRONJ (P = 0.0093), and by contrast, surgical resection was performed more frequently for ORN (P = 0.0002).

Understanding the clinical and underlying pathological differences between ORN and MRONJ probably contributes to the selection of appropriate treatment for each patient.